(a) Technical Field
The present disclosure relates to a method of controlling regenerative braking of an eco-friendly vehicle, and more particularly, to an apparatus and a method which variably controls the amount of regenerative braking based on shifting from a drive gear by a driver while driving.
(b) Background Art
Currently, internal combustion engine vehicles that use fossil fuel such as gasoline or diesel have problems including environmental contamination caused by exhaust gases, global warming by carbon dioxide, and respiratory diseases due to generation of ozone. Accordingly, eco-friendly vehicles such as an Electric Vehicle (EV) that runs by operating an electric motor, an Hydraulic Electric vehicle (HEV) that runs using an engine and an electric motor, and a Fuel Cell Electric Vehicle (FCEV) that runs by operating an electric motor, using power generated by a fuel cell have been developed.
As known in the art, eco-friendly vehicles run a regenerative braking (RB) mode that collects braking or inertia energy through electricity generation of an electric motor and charge a battery with the energy during braking or coasting by inertia of the vehicles. Since the eco-friendly vehicles collect energy, using an electric motor (e.g., driving motor) and charge a battery during braking or coasting by inertia, fuel efficiency may be improved and energy may be used more efficiently. On the other hand, one regenerative torque map is set for the drive (D) gear in eco-friendly vehicles of the related art, to obtain a constant amount of regenerative braking energy during coasting with the D-gear engaged, due to the regenerative braking torque map.
Obtainable optimum regenerative braking energy depends on the features of roads, and accordingly, the optimum regenerative braking energy may not be achieved only by the D-gear according to the known techniques. For example, more regenerative braking energy may be obtained on a steep slope compared to a gentle slope (e.g., a less inclined road) and the optimum regenerative braking energy may not be obtained only by the D-gear according to the known techniques, in regenerative braking with the shift lever at the D-gear.
Although substantial energy may be recovered in some gears compared to the D-gear, such as, an E-gear (e.g., an eco-gear used for driving in an economical mode) or a B-gear (e.g., used with an engine brake operating) with different torque maps, most drivers do not use the gears since it is cumbersome to operate the shift lever while driving. In particular, when the B-gear is used for deceleration, it may be possible to obtain large regenerative braking energy, but it may be difficult to use the gear frequently since the feeling of deceleration of a vehicle is substantial when the gear used for all of road conditions to recover substantial energy.
The above information disclosed in this section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.